An option to only remove all edits, which are marked as "minor" does not exist currently. Integrating such an option will cause problems:
First of all, it will break things like the calculation of size differences between revisions, if the referenced revision suddenly no longer is there. While this only is a technical issue, which maybe can be solved, there is another, way bigger problem:
An option to only delete minor edits will remove some edits from the history, but not others. Features like the history function of MediaWiki rely on the fact that all revisions stay in place. They compare revisions with each other and display the difference. However, if a revision in between has been removed, then the difference will also include the changes made in that removed revision. That means that changes will be attributed to a user, although it is not clear whether it was really him, who made them.
This is a very bad situation, which might even cause legal trouble, e.g. if part of an edit contains insults and with the according revision removed it looks like these insults come from user A, while they in fact have been added in a removed revision by user B.